%I #12 Apr 12 2017 18:16:27
%S 1,1,1,49,897,96801,6803457,1275363153,207592347393,
%T 60889593787713,17888210916886017,7679611833095218545,
%U 3530100224793651058305,2109645360096014314212705,1387893136694794953345211905,1109191050707015380265790041745,984063632341385922413073350925825
%N Expansion of e.g.f. of cos(arcsin(arcsinh(x))), even powers only.
%H G. C. Greubel, <a href="/A012115/b012115.txt">Table of n, a(n) for n = 0..224</a>
%e 1  1/2!*x^2 + 1/4!*x^4  49/6!*x^6 + 897/8!*x^8...
%t With[{nn = 50}, Table[(CoefficientList[Series[Cos[ArcSin[ArcSinh[x]]], {x, 0, 2*nn}], x]*Range[0, 2*nn]!)[[n]], {n, 1, 2*nn + 1, 2}]] (* _G. C. Greubel_, Apr 12 2017 *)
%o (PARI) x = 'x + O('x^40); select(x>x, Vec(serlaplace(cos(asin(asinh(x)))))) \\ _Michel Marcus_, Mar 09 2017
%Y Cf. A012248.
%K sign
%O 0,4
%A Patrick Demichel (patrick.demichel(AT)hp.com)
%E More terms from _Michel Marcus_, Mar 09 2017
